Development of a lavage procedure to collect crop secretions from live chickens for studying crop immunity.

The crop (ingluvies), an organ for food storage in most avian species, is located at the base of the oesophagus. Previous work in our laboratory showed that, following infection with Salmonella enteritidis, significant anti-S. enteritidis antibody levels could be found in the crops of these birds. Samples in these previous studies were obtained by flushing the interiors of crops excised from killed birds, which is both labour and animal intensive. A method was sought that allowed multiple sampling of the same birds over time. We found that lavage fluid could be administered directly into the crop down the oesophagus using a narrow-diameter plastic tubing attached to a syringe, and the fluid could then be aspirated back into the syringe. Antibody-containing crop secretions could be collected with minimal discomfort to the test animals. In a study where birds were challenged with S. enteritidis, immunoglobulin A anti-S. enteritidis titres 3 weeks post-challenge were similar in crop samples obtained by live lavage versus the flushing of crops removed from killed birds. Such a sampling procedure may provide researchers with a simple method to follow mucosal immunity in chickens following infection or vaccination regimens.